Comments on: Water-catching device wins Arup competition

By: Philip Jones

Philip Jones — Wed, 21 Nov 2007 20:31:17 +0000

A recent technical paper which explains the more important practical requirements (non-technicals can skip the equations) and describes a special foil which is available is: Modeling and testing of a dew collection system, Desalination vol. 180(2005)47-51 by P. Gandhidasan and H.I. Abualhamayel (Dhahran, Saudi Arabia) at http://www.desline.com/proceedings/180.shtml. Dew collection is not a new idea, and while it is good to give it some publicity, it is a pity that previous knowledge was not used to make a more informed design. For example, you wouldn’t put these near trees as that would inhibit the radiative cooling on which the process depends, and the estimated “minimum” yield of 48 L per unit is very optimistic except under the most favourable conditions. Generally, the procedure is unreliable and certainly cannot be claimed to provide useful quantities of domestic water “in almost any climate”. A quick internet search will reveal a lot of information on this topic. Dew may be a significant micro water source for some agricultural industries where small albeit intermittant quantities of dew may help a crop survive periods with no rain. See http://www.harialanzarote.com/stone_mulching.htm

By: Seyoum

Seyoum — Sun, 04 Nov 2007 08:39:04 +0000

We are an Ethiopian business company that are trying to get hold of such a highly developed technic. But we are having problems in locating which companies that are the providers. Can you help us in providing some link adress’. I’m on a visit in Sweden.

Regards
S.

By: CHARLES MORENO

CHARLES MORENO — Tue, 09 Oct 2007 21:11:59 +0000

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By: Richard Criddle

Richard Criddle — Sun, 02 Sep 2007 14:31:34 +0000

We are working with villagers in remote, near coastal areas of Peru. They have virtually no rain at these sites and water runoff from snowmelt is badly contaminated by the time it reaches these villages. Humidity is high and diurnal temperature fluctuations are significant in these areas. Thus it appears that these would be perfect sites for the inverted pyramid water extraction device.
However, I am having difficulty in locating technical information on the best materials and geometry for construction of the device. Is there a source that you can recommend for getting these details?
Thanks, Richard Criddle

By: Peter Watson

Peter Watson — Sun, 12 Aug 2007 10:17:53 +0000

I would like to buy or build one (Watair inverted pyramid) - is there a kit available please?

By: Craig Jenson

Craig Jenson — Thu, 22 Mar 2007 20:23:49 +0000

Looks like a great idea to supply water in places where the climate would regularly supply saturated air. All the places I’ve been where there are water shortages are desert climates where there are very few days with dew. How do I get climate data on historical temperatures and dewpoints? Would a simpler arrangement of tarps provide a similar result? Thanks for the good idea. As a mechanical engineer with significant knowledge of thermodynamics, I have learned that ideas are cheap and I would like to make an investment to test this idea at a few places around Southern California and Arizona. Please contact me at cjenson652@hotmail.com if you’re interested in helping me.

By: Shawn Honnick

Shawn Honnick — Thu, 01 Mar 2007 17:27:26 +0000

Fantastic idea and great work.

By: Reamon Guoqun Yu

Reamon Guoqun Yu — Thu, 01 Mar 2007 16:05:38 +0000

Good idea of turning dew into fresh water. It’s quite good I think.
But I have some concerns: The first is the quantity of the water collected, is that true that it can collect 48 L /day? As I know that the ‘ moisture in air’ become into dew has its special conditions. Either if the air reach 100 percent relative humidity, the air is saturated and water vapor can condense on the sufaces like blades of grass and car windows, so for this way it’s not suitable for WatAir in almost any climate ; or the air meets a surface cooler than the air temperature, it’s also possible to condense dew, but it has a precondition that the air is calm (or nearly calm), also how long could the glass be cooler than the air, one hour? or one night?
In addition, it’s a quite demanding work to make it stand firmly on the ground to resist strong wind in bad weather days.
But anyway I think it’s a good work in the design competition.
BTW, I have a winning work to save water for washing hands and showering. The details are here :http://www.idcn.jp/compe/compe2006/result/profile/en/silver01_e.html